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The description and representation of particle shape
Author(s) -
Benn Douglas I.,
Ballantyne Colin K.
Publication year - 1993
Publication title -
earth surface processes and landforms
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.294
H-Index - 127
eISSN - 1096-9837
pISSN - 0197-9337
DOI - 10.1002/esp.3290180709
Subject(s) - sphericity , ternary plot , distortion (music) , representation (politics) , plot (graphics) , diagram , mathematics , statistics , computer science , ternary operation , geometry , amplifier , computer network , bandwidth (computing) , politics , political science , law , programming language
Abstract Despite widespread agreement on the value of shape analysis in the study of sediments, methods of representing and summarizing data have proved difficult to standardize. This paper shows that Sneed and Folk ternary diagrams provide an appropriate standard method of representing data and a rational basis for the choice of descriptive indices and analytical methods. Such diagrams have the unique quality of representing the variation of particle shapes without bias or distortion, unlike alternative diagrams (e.g. biaxial Zingg plots). Simple descriptive shape indices plot on Sneed and Folk diagrams as straight lines, and behavioural indices (e.g. sphericity) as curves. No index or pair of indices can be regarded as ‘optimum’ in all situations: indices should be chosen with reference to particular data distributions and specific research aims. The use of ternary diagrams in studies of clast shape is illustrated using data from Slettmarkbreen, Norway.